Unknown shrub in my garden

Observed: 22nd September 2011 By: hadriana

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Added: 22nd September 2011

Description:

Plant has thorns and larger leaves with small ones on stem in between. Fruit attach directly to stem in pairs - most unusual to me. Found growing under a leylandii. Thought they were apples at first but fruits are hard and full of seeds. No idea what it is!